Apparatus for stringing tennis rackets and the like



Feb. 14, 1961 M. M. BOYKIN ETAL 2,971,760

APPARATUS FOR STRINGING TENNIS RACKETS AND THE LIKE Filed Jan. 10, 1958 2 Sheets-Sheet 1 INVENTORS' M. BOV/f/A/ 05567 0. 870.555

MAE?

ATTORNEYS Feb. 14, 1961 M. M. BOYKIN l-rrAL 2,971,760

APPARATUS FOR STRINGING TENNIS RACKETS AND THE LIKE Filed Janl 10, 1958 2 Sheets-Sheet 2 INVENTORS MAR) M soy/(W /?08EE7 0. 6705.55 BY J Ww Zm rram/Eflr Un t d s ws Pa fi o APPARATUS FOR STRINGING RACKETS AND THE LIKE Mary Morris Boykin, 189 Boulevard, Pelham, N.Y., and Robert D. Stubbs, 6310 SW. 19th Terrace, Miami, Fra.

Filed Jan. 10, 1958, Ser. No. 709,725 (Filed under Rule 47(a) and 35 U.S.C. 116) 4 Claims. (Cl. 273-73) among expert tennis players, to have a portable racketv stringing device so that the player may restring his own racket. Professional tennis players frequently travel to different sections of the country during the various seasons which requires that they have a small, inexpensive stringing apparatus which can be carried or stored in compact areas. The present device includes a portable construction and yet it is inexpensive, sturdy and simple to operate. The device may be placed and 'used anywhere such as on a kitchen table, piano bench or-work table.

, When operating the present stringing device one may remain seated and by pushing a release buttonrotate the racket to any desired position. Therefore, the operator can always be working toward himself which is the most desired position.

The vise for holding the racket frame as disclosed has adjustable clamps which move in a horizontal plane. Thus, the device may not only be used to string tennis rackets but is also adjustable for stringing badminton or squash rackets and the like.

The construction of the present device furnishes ample working area above and below the frame. This unobstructed area provides adequate hand room for the operator while weaving the cross strings.

The top of the base of the device may have a rough exposed surface finish which makes a convenient and accessible place for razor blades, shellac brushes and other necessary utensils used during the process of stringing the racket.

An object of the invention is to provide an apparatus for stringing rackets which has a string ten'sioning device that can be manually operated to pull the string to a precalculated tension which does not depend on the harmonic vibration of a string This tensioning device does not include any spring members and may be easily adjusted to pull the strings to any degree of tautness desired by the operator without exerting physical strength to twist the string around a winding stick.

A still further object of this device is to provide a free working area both above and below the racket allowing the operator the benefit of stringing the racket from the bottom as well as the top sides with agility and convenience.

A still further object of the device is to provide a portable stringing apparatus which is light in weight, inexpensive to construct and may be carried with ease in a standard tennis case.

Other objects and features of this invention will become 7 I apparent in the following description and claims as well as in the drawings.

In the drawings:

Figure 1 is a top plan view of the device showing the racket in place and a string being tightened by the tensiometer;

Figure 2 is a side of the base removed;

Figure 3 is an enlarged detailed cross-sectional view of the frame holding clamps taken along line 33 of Fig. 1.

- Figure 4 is a partial detailed view of the cog wheel and plan view of Fig. 1 with a section I locking mechanism.

Another object of this invention is to provide a frame said frame; a tensiometer or device for applying a pre determined degree of tension to each string as it is being threaded within said frame; and base for mounting said tensiometer at a spaced distance from the vise and for mounting said vise and the mechanism controlling and locking its rotation through 360".

Referring more in detail to the accompanying drawings and more particularly to Figs. 1 and 2, a racket frame 10 having a plurality of strings 11 is held in the device and has a string 12 in the process of being pulled. The device is provided with an elongated oval shape base 13. This base is hollow and may be constructed of cast aluminum with a semismooth finish. Felt, cloth, rubber or other protective coating may be attached to the bottom to prevent scratching and slipping. Rotatably connected to one end of the base 13 by a bearing bolt 72 or the like is a vertical upwardly extending arm 14 transversely cylindrical or drum shaped at its upper end 15. Arm 14 is rotated to cooperate with the position of racket frame 10 and the particular string 12 being pulled. Formed on the periphery of the outer vertical surface of this drum shaped section is a plurality of elongated outwardly extending teeth 16. Attached to the inner vertical surface of drum 15 in a juxtaposed position is a circular disc ratchet plate 17 having a plurality of angular teeth 18 upwardly extending from its circumference. The elongated teeth 16 on the outer vertical surface of the drum shaped section 15 correspond with the upwardly extending teeth 18 on ratchet plate 17. Ratchet plate 17 is suitably held to drum 15 by countersunk fiat head screws 19 or the like. The top of drum 15 is provided with a calibrated scale 20 which extends over the periphery of the top of said drum. Said calibrated scale 20 is preferably divided into units of five with each of said units corresponding to the teeth 16 and 18. Thus, the first I proceeding in a counter clockwise direction, would correspend to a five reading on the calibrated scale; the third tooth to ten, etc. As will be shown later, there is direct cooperation between said teethand said scale in regulating the tension of the strings being pulled.

Centrally located and passing through drum 15 and plate 17 is a bearing opening 21 to accommodate a bearing pin or bolt 22 threaded at one end.

Cooperating with said calibrated scale 29 is a stop plate 23, illustrated in Fig. 7 having an elongated central section 24 and a right angled arm section 27 extending from one end thereof. Said central section 24 has a plurality of elongated inwardly extending teeth 25, said teeth protruding in the same direction as arm'section 27. The teeth 25 of the stop. plate 23 register with the elon-v gated side teeth 16 on the outer surface Of drum shaped section 15. Central section 24 has a bearingopening 26 to accommodate the threaded end of; bolt 22 which extends through said opening. When the stop plate'23 is guided over said bolt the right angled arm section 27 extends over the calibrated scale 24 and the, teeth 25 register with teeth 16. A Wing nut 28 cooperating with the extended threaded end of bolt 22 holds the stop plate 23 in its set position.

On the other side of plate 17 is a handle 29 having an extended arm section 30 and a drum head section 31. Said drum head section 31 is juxtaposed to said plate 17 and has a centrally disposed bearing opening 32 which registers with hearing openings 21 and 26 and accommodates bolt 22. 'As shown in Fig. 2, the diameter of the drum, head section 31 is larger thanthe diameter. of plate 17 allowing it to extend vertically above the teeth 18 on said plate. With this construction, there is no chance for the string to be caught orcut by teeth.- 18.

Affixed to the top of handle 29 approximately where the arm section 3f0formsthe-drum section 31 and extend. ing forwardly is a spring. press pawl 33 which has an angular extending section 34 adapted to register with teeth 18 of plate 17. When the angular extending section 34. of the pawl isengaged with the plate teeth 18 it prevents the handle from counter rotation. To disengage the pawl 33 the end of the pawl 35 is pressed downwardly against the pressure of spring 36 lifting, the forward section 34 upwardly and disengaging it from. teeth. 18. When the pawl is pressed in this manner, handle 29 maybe reciprocated in a counter clockwise rotation. The handle 29 can always berotated in a clockwisedirection becauseof: the backwardly angled teeth 18 as shown in Fig. 2. When the handle is rotated in a clockwise direction. the extending section 34 Oli'pafWl 33 slips over onetooth and falls into the succeeding tooth by the. force of pressure spring 36.

Suitable means are attached to the side of handle 29 for tensioning the string or gut pulled through the racket. Figs. and 6 disclose one means for coiling the gut around a disc 37 having chamfered edge SS and a notch 39 and overlapped by clip 40,. which has. an outwardly angled end and side 41. The disc 37 is alfixed to the drum head section 31 of handle 29 by flat head screws 43 or the like. Clip 40 is aifixed to drum head 31 by a machine screw 42 which passes through plate 37. Plate 37 and clip 40 are provided with centrally disposed bearing openings for bolt 22. Bolt 22 passes through clip 40, plate 37, handle drum head 31, ratchet plate 17, drum head 15 and stop plate 23 and is. secured at its threaded end by nut 28 holding. the aforementioned pieces-freely together in an operativemanner. i

As shown in Fig. 6, the gut or. string 12 being tensioned is drawn taut by leading it into the groove formed by the chamfered edge 330i plate 37 and the handle drum head 31 through the. notch 39, thenceunder the angled side and end 41 of clip 40 where it is wedged between plate 37 and clip 40..

It can readily be seen in Fig. 5 that by rotating handle 29 downwardly, plate. 37 andclip 40will rotate in a 4 counter clockwise motion (clockwise in Fig. 2). At the same time, the string will be wound around the plate and a tension created in the string. The amount of tension on the string will depend upon the distance the handle is rotated downwardly.

The distance that the handle is rotated is determined by the setting of the right angled arm 27 of stopplate 23 over the calibrated scale 20. To set the stop plate to the desired tension the wing nut 28 first loosened and the stop plate is moved so that arm 27 extends over the desired numerical position on the calibrated scale. When the teeth 25 of the stop plate and the teeth 16 on the sides of drum 15 register the wing nut 28 is'tightened which prevents movement of the stop plate. When the handle is now rotated as shown in Fig. 2 in a counter clockwise rotation, the top extension of pawl 33 contacts the angular portion of stop plate 27 which has been set at the predetermined tension calibration. When the handle 29 is rotated downwardly, this predetermined tension is pulled on the string. It should be noted that once the stop plate has been set the same tension will be exerted on each string without any resettings or new calculations.

At the other end of base 13 is a vise comprising a circular shaped base 44 having a pair of upwardly and outwardly opposed arms 45 fixed in a spaced relative position. Said base 44 and arms are capable of rotary motion through 360. The circular arm base 44 rests on a raised section 46 of base 13 which forms a housing for a horizontally aligned cog wheel 47 having an upwardly extending collar 48. The circular arm base 44 is fastened to the collar 48 of the cog wheel 47 by screws 49 or the like. There is a close bearing surface between the. sides of collar 48, theupper surface 71 of cog-wheel- 47 and the inside surface of the raised base section 46 to govern therotation of said arm base 44.

The cog wheel 47 has a plurality ofteeth 50 preferably thirty-six, and rotates on a horizontal plane. Housed within the hollow base 13 and extending in a longitudinal plane is a locking rod 51. One end of said rod is pointed 52 as shown in Fig. 4, to mesh or lock-within theteeth 50 of cog wheel 47. The other end of the lockingrod 51 is affixed to a bell crank lever 53 at- 54, said lever having linked to its other end a vertical actuating press button 55 and 56 which extends upwardly through the base 13. To maintain the locking rod in a forward or locked position a coil spring 57 may be suitably attached to the casing and rod. Referring now to Fig. 2, the locking rod is shown in a locked position, preventing the cog wheel 47, collar 48 and arm base 44 from rotating. By depressing the press button 55, the bell crank lever retracts the locking rod out of mesh with the teeth 50 of wheel 47 allowing said wheel, sleeve and arm base to be rotated to any desired position. When the desired position has been reached, the press button is released allowing the coil spring to retract and permitting locking the arm into mesh with the cog wheel teeth, thus preventing the arm base from moving.

At the upwardly extending ends of the frame holding arms 45 are two adjustable clamps. One clamp is for a horizontal adjustment to compensate for rackets of varying sizes and shapes such as badminton or squash rackets. The other set ofadjustable clamps operate in a vertical plane and hold the racket head firmly in a fixed horizontal plane. As shown in Fig. 2 and in more detail in Fig. 3, 58 is the horizontal adjustable clamp. Said clamp has at its upper side an elliptical lip 59 to fit the interior contour of the racket head frame and to hold the racket from warping when being strung. The horizontal adjustable clamp 58 is connected to a threaded adjusting pin 60 which passes through the frame holderv 45 at bearing opening 61. The. outwardly ex tending end of pin 60 is threaded into a hand adjusting nut 62. By turning the hand adjusting nut in a clockwise rotation, pin 60 is drawn through bearing opening '61 and forces the horizontal adjusting clamp 58 away from the opposite frame holder, thus increasing the distance between the two clamps 58. By unscrewing the adjusting nut 62 the distance between the horizontal adjusting clamps is decreased permitting smaller rackets to be fitted around the lips 59 and held firmly in a fixed horizontal plane. To assist in guiding the horizontal movement of clamps 58 suitable guide pins 63 may be provided. As shown in Fig. 3, it is preferable to have said pins threaded at one end 64 and screwed into clamp 58 and pass through a bearing opening 65 in the frame holding arms 45 The vertical racket holding clamp 66 has extending lips 67 which overlap the top of the racket frame and is slidably held by a threaded pin 68 which extends in a vertical plane into clamp 58. Threaded to the top of said vertical pin is a removable wing nut 69. When positioning the racket in the holding frame wing nut 69 is removed along with clamp 66. After the racket head has been fitted within the lips 59 of horizontal adjusting clamps 53, the racket frame holding clamps 66 are replaced and the wing screw tightened so that the lips 67 of clamp 66 presses firmly against the top side of the racket frame while lip 59 of clamp 58 presses firmly against the bottom side.

The device may be made of castings which are sturdy and inexpensive. The weight of the device should be less than ten pounds and may, if necessary, be dismantled for convenient packing. The base of the device may be provided with an extending flange 70 for conveniently attaching it to a table with C clamps or the like. If desired, holes may also be provided within the base to allow for permanent mounting.

It is obvious from the foregoing description that this invention embodies a racket stringing device comprising a minimum of movable parts which are simple in construction and operation. The device does not require special tools nor are there complicated gear connections, base stands and the like. There are no parts which will break because of fragility or require replacement due to wear. The device may be disassembled for cleaning or storing without complication.

It has been found that when stringing a racket head with gut, factors such as humidity in the air or temperature may cause the strings to be tensioned at a slightly different force than that set on the tensiometer. This may be particularly true of the main strings which run the length of the racket. Ordinarily when the stringer discovers that the atmospheric conditions-have affected his gut he would have to remove the main strings and re-tension. However, with the present device the stringer need only tighten or untighten adjusting nut 62, thus forcing the horizontal adjusting clamps away from or toward each other. This tightens all the main strings evenly with the most negligible elongation or contraction of the racket head frame.

Although one embodiment of this invention has been shown and described herein, it is understood that certain changes and additions can be made without departing from the spirit and scope of this invention.

We claim:

1. A portable device for stringing tennis rackets and the like comprising a base, a pair of rotatably opposed spaced vertical arms at one end of said base, each of said arms having an opposed horizontally movable racket frame holding clamps, opposed horizontal pins mounted in said clamps and through said frame, means for moving said pins inwardly whereby said clamps are moved inwardly decreasing the distance between said clamps, pressure means above said clamps, said means pressing downwardly on the racket frame when said frame is held in the racket holding clamps, a cog wheel having a collar afiixed to said vertical arms within said base, a longitudinally adjustable locking rod fitted in said wheel,

gear means connected to said rod whereby it may be moved into and out of a locking position, a string tensioning device connected to the other end of said base having a vertically extending arm, said arm being drum shaped at one end, a calibrated tensioning scale on said drum, an adjustable stop plate overlapping said scale, a reciprocally rotatable handle centrally pivoted at said drum, pawl means on said handle to cooperate with said stop plate over said calibrated scale to prevent upward motion, a string winding plate afiixed to said handle at said pivot, and counter rotation locking means on said handle.

- 2. A device for stringing tennisrackets and the like comprising a base, a string tensioning device mounted at one end thereof having a vertical stand drum shaped at its upwardly extending end, said drum having a cali brated upper surface, a toothed sector on one side and a toothed plate attached to the other side,- a bearing'bolt passing through said stand, drum and plate, an adjustable stop plate connected to said bolt and passing over said calibrated drum whereby a predetermined tension may be calculated and applied to a string to be pulled, tightening means for holding said stop plate in a fixed position, a reciprocal rotatable handle connected to said bearing bolt, said handle having a spring pressed pawl registering with said toothed plate and in the path of said stop plate, a clip aflixed to said handle at said hearing bolt and having a guide plate whereby string or gut may be attached therearound and tensioned with the rotation of said handle, a rotatable racket frame holding means mounted at the other end of said base, a cog wheel atfixed Within said base, lever means for locking said wheel in a fixed position, a racket head holding frame affixed to said wheel having outwardly and upwardly extending arms, the end of each of said arms having an adjustable horizontal frame clamp, an adjustable vertical racket frame holding clamp and means for adjusting said horizontal and vertical clamps.

3. A device for stringing tennis rackets and the like comprising a base having a vertical bearing stand mounted at one end thereof, said stand having at its upwardly extending end a drum calibrated on its upper surface, said drum having a toothed sector on one side and a toothed plate afiixed to the other side, a bearing opening passing through said stand, drum and plate, a bearing bolt passing through said opening, a right angle adjustable stop plate cooperating with said bolt having one arm extending over said calibrated drum, said stop plate provided with side teeth to register with the toothed sector of the drum, a handle rotatable about said bearing bolt having a spring pressed pawl, the forward end of said pawl registering with the toothed plate thereby holding the handle against counter rotation, means affixed to said handle at said bearing bolt whereby string or gut is pulled therearound when said handle is reciprocated,

a rotatable racket holding frame mounted at the other end of said base, gear means for adjusting and holding said racket frame holder in various fixed positions, said racket holding frame having a pair of opposed outwardly and upwardly extending arms, horizontally adjustable racket head holding means at the end of said arms, vertically adjustable racket head holding means at the top of said arms whereby said means firmly hold rackets of varying sizes in a fixed and firm horizontal position.

4. A device for stringing tennis rackets. and the like comprising a base having a vertical bearing stand mounted at one .end thereof, said stand having at its upwardly extending end a calibrated drum with a toothed sector on one side and a toothed plate attached to the other side, a bearing opening passing through said stand, drum and plate, a bearing bolt passing through said opening, an adjustable right angle stop plate cooperating with said bolt and having one arm extending over said calibrated drum and toothed plate, said stop plate providedj with teeth to register with the toothed sector of the drum, a reciprocal rotatable handle cooperating with said bearing bolt, said handle provided with a spring pressed pawl registering with said toothed plate and having a forward extending end, said forward end cooperating with said stop plate whereby a predetermined tension may be calculated and applied to a string to be pulled, means on the side of said handle at said bearing bolt for coiling a string to be pulled therearound where; by a tension is exerted on said string when said handle is reciprocated, a rotatable racket ,frame holder mounted, at the other end of said base, gear means for adjusting and holding said racket frame, holder in various fixed positions, said frame holder having outwardly and, up-

wardly eigtending arms, the end of each ofsaid arms having an adjustable horizontal racket head frameclamp,

an adjustable vertical racket head frame holding, clamp and means for adjusting said horizontal and, vertical 10; 2 ,389,609, :Caro et al., Nov. 27, 1945 FOREIGN PATENTS 617,288 Great Britain Feb. 3, 1949 

